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US69 Des Moines River Bridge

Photos 

North Approach To Se 14th Street Bridge Crossing The Des Moines River, Looking South

Photo by Bruce A. Harms, LBA; Summer 1996, for HAER

View photos at Library of Congress

BH Photo #123712

The Significance of the SE 14th Street Bridge 

Condensed from the HAER report by Richard Vidutis and James Hippen, Summer 1996

The SE 14th Street Bridge, in addition to responding to the always difficult problem of getting to the various parts of Des Moines with two major rivers joining in the center of the city, provided a necessary relief to highway traffic that had to thread its way through the center of the city. US 65 (the old Jefferson Highway) passed through Des Moines on the way from Canada to the Gulf of Mexico. The new bridge, along with its northerly companion, the SE 14th Street Viaduct over the railroad yards, kept highway traffic away from downtown, and provided imporved access to the state capitol. [Editor's Note: For another interesting Jefferson Highway bridge in Iowa, see the Lincoln Highway Colo Interchange.]

Iowa was conforming to at least two national trends in the building of this bridge. There was the choice of a continuous design and there was the assisatnce from the federal government to help relieve the unemployment brought on by the Great Depression. Shortridge Hardesty, of Waddell & Hardesty, Consulting Engineers, in reviewing the bridge engineering for the year 1936 noted that "there was a large volume of moderate-sized and small bridge work under way during the year, much of it with the aid of PWA and other federal money." Albin L. Gemeny, Senior Structural Engineer, U.S. Bureau of Public Roads, noted a year later that "there was a continuing inclination among engineers toward the use of steel, instead of concrete, for structures where these two materials were competitive." And he made another point which accurately described the SE 14th Street Bridge. Gemeny wrote that "in the field of steel bridges mulitple simple spans have almost gone into the discard. Continuous beam and girder spans are being generally adopted for intermediate lengths."

The SE 14th Street crossing built in 1936-37 was a 750' deck plate girder bridge, two 105' spans and four 135' spans. The six spans were each six girders wide. The riveted plate girders are in the order 105-135-135-135-135-105.

The bridge was a completely successful exercise in the use of continuous technology, and has lasted well to the present. Its only flaw, shared by so many bridges of that era, was that it could not forever handle the constant increase in motor traffic. Consequently, in 1971 a design was prepared to widen the bridge. This was accomplished very neatly by adding concrete corbels to the ends of the original piers, sliding the original appearance of the bridge while adding to its capacity. Today the bridge maintains its elegant efficiency in carrying traffic, and it demonstrates the high quality of bridge design construction of the 1930s.

Facts 

Overview
Haunched steel stringer bridge over Des Moines River on US 69 in Des Moines
Location
Des Moines, Polk County, Iowa
Status
Open to traffic
History
Built 1936; rehabilitated 1973
Builders
- E.A. Kramme Co. of Des Moines, Iowa
- Iowa State Highway Commission of Ames, Iowa
- Sverdrup & Parcel of St. Louis, Missouri (Designer)
Design
"The SE 14th Street Bridge maintains its original appearance while demonstrating the high quality of bridge design and construction in the 1930s of continuous span technology.

"This document was prepared as part of the Iowa Historic Bridges Recording Project performed durng the Summer of 1995 by the Historic American Engineering Record (HAER). The project was sponsored by the Iowa Department of Transportation (IDOT). Preliminary research on this bridge was performed by Clayton B. Fraser of Fraserdesign, Loveland, CO."

Historians: Richard Vidutis and James Hippen, Summer 1996
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Dimensions
Length of largest span: 135.2 ft.
Total length: 758.2 ft.
Deck width: 56.8 ft.
Also called
SE 14th Street Bridge
Approximate latitude, longitude
+41.57563, -93.59700   (decimal degrees)
41°34'32" N, 93°35'49" W   (degrees°minutes'seconds")
Approximate UTM coordinates
15/450230/4602832 (zone/easting/northing)
Quadrangle map:
Des Moines SE
Average daily traffic (as of 2015)
31,300
Inventory numbers
IA 40500 (Iowa bridge number)
BH 37420 (Bridgehunter.com ID)
Inspection report (as of February 2017)
Overall condition: Fair
Superstructure condition rating: Satisfactory (6 out of 9)
Substructure condition rating: Fair (5 out of 9)
Deck condition rating: Fair (5 out of 9)
Sufficiency rating: 80.8 (out of 100)
View more at BridgeReports.com

Update Log 

  • June 4, 2013: Updated by Luke Harden: Corrected pin location
  • September 13, 2008: Essay added by J.R. Manning

Sources 

  • J.R. Manning - thekitchenguy [at] sbcglobal [dot] net
  • HAER IA-84 - Southeast Fourteenth Street Bridge
  • Luke